moses



2 sheen-sheet 1.

\ (No Model.)

o. A. M0858. INGANDESCENT ELECTRIC LAMP.

N5. 825,958. Patented sept. .8, 1885.

4 .5 m mw Ff .5

S14/uente@ N. I'EYERS. Phuwumngnphor. Vlamingen. 0,6.

2 ShBtS--Shegt' 2;

(No Model.)

o. An/10888 INGANDESGENT? BLBGTRIQLAMP.

Patented 881188,*1885;

qUNiTnD STATES y PATENT Ormea@ OTTO A. MOSES, OF NEW YORK, N. Y.

INCANDESCENT ELECTRIC LAMP.

SPECIFICATION forming .part of Letters Ptent No. 325,958, datedSeptember 8,1885. v

1 Applicationled July 30, 1884. (No model.) i

To @ZZ whom it may concern.-

Be it known that I, OTTO A. Mosus, a citizen of the United States,residing in the city, county, and State of New York,have inventedcertain new and useful Improvements in Incandescent Electric Lamps, ofwhich the following is a specification.

This invention relates to the class of electric lamps in which theconductingstrip, wire, or filament of carbon, hydrocarbon, or othersuitable refractory substance is inclosed within a transparent airtightglobe or chamber from which the air is exhausted and which may or maynot be filled with a non-oxidizing gas or vapor.

The invention claimed in this application relates particularly to theform and construction of the filaments and tothe method of inserting thesame within the inclosing chamber; but a complete description will begiven of the entire lamp and ofthe process of manufacturing the saine,for the purpose of more fully setting forth the invention and itsapplica tion.

In the construction of inclosiiig globes or chambersforincandescentlights it is desirable that the globe itself should be soformed that it will not be liable to crack or break when unevenly heatedby the current employed for rendering the filament incandescent; that itshall be of uniform thickness and offer aslittl'e opportunity aspossible for the ,formation ot' rings or shadows by refraction, and thatthe entire process of shaping, exhausting, and sealing the globe orvacuunrchamber should be simple and effective.v For this purpose it isdesirable that the several elementsV comprised in the lamp-namely, theglobe, thel incandescing filament, its supporting-conductors, and thesupporting-cup-in connection with which the completed lamp is to beemployed should be each adapted in form and construction to the otherparts. In setting forth this invention, therefore7 a completedescription will be given of the process of forining and manufacturingall these several parts of the lamp, together with the description ofthe formation of the globe and process of exhausting and closing thesame.

The globe is constructed of a single piece of glass, which is preferablyblown into a mold,

whereby all the lamps are rendered uniform the air after the conductorshave been secured in place. This is rendered unnecessary for the reasonthat by this invention the globe is exhausted and closed at the end ator near which the conductors enter. The neck of the globe is afterwardnarrowed or diminished in size, and it is cut or broken off by asuitable tool near the bulb or globe. The conductingfilament,which willbe hereinafter described, is then inserted within the globe, and theconducting-wires leading to the saine are suspended across the edge ofthe neck of the globe. B means of a blowpipe the glass is then heated4about the conducting-Wires, which are preferably of platinum. Thewires, by reason of their own weight, sink into the glass as it becomessoftened, and the glass closes above them. If, however, this actionshould not take place quick ly enough, a little particle ofglass isfused upon the exposed platinum wire restingon the globe for the purposeofholding the conductors and the filament firmly during the subsequentmanipulations. The portion of the neck which was at rst cut off is thenplaced against the neck from which it was removed, and the two arewelded together by means of a blow-pipe, the two parts occupying thesamerelative positions as those they originally held. A platinum or othersuitable metallic stopper is then inserted Within the neck formed of thetwo sections which have been thus welded together into a Whole tube, andthe tube is then preferably drawn to a diameter that will prevent thestopper from falling out, or it may be curved to an angle for the samepurpose. The air is then exhausted from the globe and the glass issoftened around the stopper at the lowest possible temperature andcaused to be compressed against the same. rounding atmosphere iscompressing the softened glass around the pin or stopper the glass neckis elongated to still further insure the close tting of the pin to theneck of the tube Which'joins the lamp to the air-pump. In the vsides ofthe neck there are preferably formed. slight depressions,which affordpoints for the While the sur- IOO holder to grasp the lainp and retainit in its proper position. The neck of the globe or chamber is, however,preferably otherwise straight.

rlhe form of carbon which it is preferable to employ in this globeconsists of a carbonized filament formed in the shape of two incompletecircles having preferably slightly different diameters and united witheach other by a curved continuation of the filament. The circles ofdifferent diameters serve a special purpose in preventing a continuedmovement of the filament, when the lamp is jarred, by breaking up thevibrations into ones of smaller amplitude. The form of the filament isalso of especial advantage for producing and radiating as equal anamount of light as possible from a given length of conductor,and that,too, within as small an area of containing-globe as possible. It hasheretofore been proposed to bend a filament upon itself at a sharp angleand to separate the sides or hold them apart by a block or wedge ofinsulating material. rllhe bent or angled portion is turned or curvedforward so that the sides form parallel curves. A filament so shaped,however, is very liable to break at the sharp angle through which thetwo sides unite with each other, and it is at the same time difficult toconstruct. By curving the portion uniting the two sides a much strongerand more desirable form is secured. Again, the sides of the loops beingparallel with each other and of the same curvature, the light from theinner surface of the one is more or less cut off by the other side ofthe filament. By having the curves of different radii a broader unobstructed area or radiating-surface is presented.

lhe supporting conducting-wires for the filament are united thereto bymeans of a peculiar form of clamp, which is formed at the end of eachwire. This clamp is made by forming an enlargement at one end and thencausing the enlargement to be flattened into a disk. The disks aredoubled, preferably, in the axis of the wire, so that two lips areformed, which are intended to receive the filament between them. Thelips are then together bent out laterally, so that they project from`the Ywire at right angles. vOne ofA these conducting-wires is appliedto cach extremity of the filament, and they are preferably so ai'-ranged that the lips of the clamps are turned in toward eachother, so asto make use of the resilience ot' the carbon loopl in case of adefective clamping.

Y For the purpose of handling the delicate filaments with facility inintroducing the ends into the clamps and for rendering the connectionbetween the ends of' the filament and supporting-conductors as perfectas possible, the ends of' the filament are preferably coated with metalby electrolysis before they are applied to the clamps. The metalliccoatings may then be forcibly brought into intimate contact with theclamps by crushing the ends of the filament contained therein. They mayafterward be soldered to the clamps, if it is desired.

A suitable bridge-piece of glasspreferably unites thesupporting-conductors with each other, for the purpose of stiffening thesame and preventing the filament from being displaced.

The operation of coating the ends of the filament with copper or othermetal, as well as the details of the construction of the lamp andholder, will be described in connection with the accompanying drawings,in whichd Figure 1 illustrates a complete lamp, together with itsholder. Fig. 2 is a side view of the incandescing filament. Figs. 3, 4,and 5 illustrate the mold employed for carbonizing the filament and themethod of removing the filaments therefrom. Figs. 6 and 7 illustrate theapparatus employed for coating the ends of the filament. Figs. 8, 9, 10,and 1l illustrate the construction of and the method of manufacturingthe supporting-conductors. Fig. 12 illustratesthe form of the globebefore the filament has been inserted; and Fig. 13 illustrates themethod of inserting the conducting-wires after the section ofthe neck ofthe globe has been removed. Figs. 14 and 15 illustrate the process ofclosing the globe. Figs. 16 and 17 illustrate certain detailsin the formand construction of the holder.

Referring to Figs. 1, 2, 3, and 4, a description will first be given ofthe incandescing filament and the process of forming and manufacturingthe saine.

rllhe filament H is constructed from a single piece of cane, bamboo,parchmentized paper, thread, woody ber, or other suitable carbonaceousmaterial, by being subjectedV in a suitable mold to a very hightemperature. The form of the filament which is preferred may bedescribed as a loop bent upon itself so as to form two incompletecircles, the one of wliich,h,is preferably of greater diameter than theother,h2. The curved end, 71,3, of the loop unites the two incompletecircles with each other and is at rightangles to them. It may here beobserved that an especial advantage is derived from having the twocircles of' the loopof different diameters-namely, that is, neithercircle intercepts the path of the other when the lamp is viewed from oneside,

vbutthe light emitted from each circle is radiated independently of theother. Such a filament is preferably formed by means of a mold of thecharacter illustrated in Figs. 3 and 4. rlhis inold,which is preferablyformed of nickel or some form of iron, steel, or carbon, orhydrocarbon,consists of an outer case,H,and an` inner section, H2. Thecase H has a central bore, li*,of greater diameter at one eXtremityJL,than at the otlieigh. Vithin the bore h4 it is designed that the sectionH2,constituting a stopper or a plug, shall be inserted. The section H2of themold tapers at the same angle as the bore l1.4 of the portion H.The two conical contactsurfaces of the sections H. and H2 are groundsmooth for the purpose of making ICO IIO

the joint as perfect as possible. surface of the ,section H spiralgrooves, k and k2, joined at their inner ends, as shown at k3, by acurved continuation of the grooves. The portion k3 of the mold ispreferably cut under slightly for the purpose of preventing the filamentfrom slipping out of lthe groove. The spiral grooves, starting from theportion k3, pass outward toward the respective ends of the section H2 ofthe molds. It is not essential, however, that the grooves should in allinstances be spiral, Vas they may be made parallel. It is designed thatthe lilament to be carbonized shall be laid in this groove, being woundabout the plug H2. The plug or section H2 is then inserted within thesection H and driven tightlyinto place. .The mold is then placed inasuitable kiln,with the smaller. endof the tapered lbore downward, andwhile in the kiln it is subjected to a sufiicient heat to et't'ect thecarbonization ot' the iilament.

It is essential that the mold should be perfectly tight during theprocess of carbonization, and this is one of the objects of tapering thebore h4. lt is evident that during the process of heating the mold theouter section H will expand, causing the diameter of the bore toincrease. The section H2, however, may thereupon drop farther into thesection H and continue to keep thejoint between the two tight. Thesection H2 afterward,as it becomes thoroughly heated, expands still moreand binds tightly against the inner surface of the bore. The plug H2 ismade hollow,so that the heat of the kiln may enter the same and morequickly penetrate the filament which is being carbonized.

The filament, after it has vbeen placed in the groove of the mold, maywith advantage be covered and held in position by means of a threadwound about the same and covering it more or less. Such a thread notonly serves to hold the lament in position, but also serves Upon the toprevent the filament from being converted4 into carbonio oxide orcarboniclacid gas in the event that any oxygen should be present. InFig. 5 there is'illustrated a mold especially adapted to permit such athread to be lapplied. In this mold grooves are made for two n'laments,and instead of being spiral in form they are made in the form ofcomplete circles, the grooves la* and k being, respectively, intended toreceive the two limbs of the iila ment, while the .portion k serves ytoconnect thesame. Atpointskland kslightdepressions are made for thepurpose of permitting the thread to pass across the filament.

It is well known that during the process of carbonizing the filamentsshrink a considerable portion of their length. It is desirable that theyshould be maintained under tension throughout their lengths during thetime such shrinkage takes place. The pressure of the lament against thesides of thel groove in which it is placed secures precisely thisresult, andan even tension is placed upon the same there are cut two.

throughout its length', although a similar re` sult could be obtained byfastening the end or ends ot' the filament before and duringcarbonization.

It may be found desirable in some instances to cover the filament afterit has been placed in the mold with carbonaceous material for thepurpose of more thoroughlyl protecting it from any oxygen which may gainaccess thereto. This may be accomplished by covering the filament, asalready stated," with a thread wrapped about in the groove or coating itwith some substance easily applied and melted or distilledaway, likewaxor parafine. 'Y

ln practice it is found that when the molds are of iron more or less ofthe carbon of the iilament will enter into the iron,forming steelthroughout the immediate `surfaces of the grooves. For thepurpose ofavoidingsuch destruction of the laments, the moldsmay be made of carbonor of some other metal than iron or nickel; but it is preferred to makethem of iron and to electroplate thesurfaces of the grooves with nickel.This may be readily accomplished by any of the well-known methods ofelectroplating. i i

It is necessary to provide some means for removing the filament from themold after-it has been completely carbonized without do ing injury toit. .When it is desired to remove the filament after carbonizing, themoldV is dropped over a rod, m, (showninFig. 4,) which is approximatelythe size of the` interior bore ofthe plug H. The rod is cool, and has,therefore, the effect of cooling the interior of the mold more rapidlythan the exterior, and thus to produce a consequent contraction of theinterior section H2. The rod m extends from a base, m', and isconstructed with a screw-thread, m2, upon Vthe rod, designed to receivea suitable nut, m3. This nut is employed to press against a angedwasher, m4, which is placedupon the rod after the mold has been placedin position. The flange m5 of the washer rests against the upper end ofthe mold-section H. By turning the nut m3 downward the washer pressesthe outer section, H', of the mold downward, causing IOO IKO

it to slip 'by the section H2, the lower end ot' I which is engaged' byan annular shoulder, m, formed at the base of the rod m. A slightmovement of the outer section, H', at once separates the two sections ofthe mold, and the section H2, containing the carbonized filament, maythen be readily removed from the outersection without bringing thelament into contact therewith, being guided by the rod m. The filamentis then removed from the mold, it being suihoiently exibleto allow ofits being bent or sprung outward.

It is desirable that the` filament should be subjected to as high atemperature as possible before it is finally placed in the lamp, for thehigher the temperature to which it is exposed the more hard, tough, andiirm will it become. The temperature to which the lamenis may be exposedin the molds is limited to the capacity of the molds to resist the heatand not themselves become melted. When, therefore, the filaments areremoved from the molds, it is preferable to pack them in loose carbonpowder, and while thus packed they may be subjected to as hightemperatures as may be desired. rlhe carbon powder may for conveniencebe contained in boxes or crucibles made of carbon, clay, or otherrefractory material, and'a large number may be treated in the same bath.rlhey will be found to retain their shapes during this treatment, andwhen removed from the carbon powder will be found to be exceedingly hardand tough. The surrounding carbon powder prevents also the access of airto the iilaments both during the process of heating and during the timethe filaments are being cooled.

The next step in the process of manufacture is that of electroplatingthe ends of the lament. The metal which it is usually preferable toemploy for this purpose is copper,but other metals may be employed. Forthis purn pose an apparatus of the character illustrated in Figs. 6 and7 is employed. This apparatus consists of a clamp, N, having its endssplit or cut apart, as shown at n and a2, and provided with set-screwsn3 n3. The ends of the iilament are respectively placed in the ends aand n2 of the clamp, and securely held in position by means of theclamping or set screws n3. The entire clamp is thus suspended in anysuitable manner with the ends in an electroplating bath, as shown at O,the curved or bent portion of the filament 'extending outside of thebath, as shown in the drawings. Any suitable process of electroplatingmay then be employed. In the drawings I have shown a battery having onepole connected with the clamp N by a wire or supporting-rod and theother with a copper electrode, 0. tact which exists between the metallicsuspending-clamp N and theends of the ilament only a short time isrequired to completely coat the ends of the filament with copper. Afterthis is accomplished the lament may be removed from the bath, and may bevery conveniently handled by taking hold of the copper-plated ends. Theends will bear avery considerablepressure whenthus coated, whereas theyare very easily fractured when not so coated. The portions of thefilament which were held by the clamps may, if it is so desired, be cutorf, the filament having in the rst place been made of such length as toallow of such portions being removed. By so cutting off the ends of thefilament the extremities are left bare-that is to say, not covered bythe metal'. This is of especial advantage, because during the process ofcuring the lilament the fluids contained therein tend to be driven andto collect at the cooler portionsthat is to say, near the ends which arein contact with the support. Now, if the ends were completely covered,the iiuids would be con- Owing to the form ofthe conlined in the carbonsurrounded by the metal, but the extremities being open they readilyescape therethrough.

The next step in the process of manufacturing the lamp consists inclamping the ends of the electrodes into the supportingcondnctors forthe same. Each of these conductors is made in a manner which will bedescribed in connection with Figs. 8, 9, 10, and 1l. At the end of apiece of platinum wire, F, there is fused a globule or ball, f. Thisball is either hammered or compressed into a flat disk. The two halvesof the disk are bent toward each other, in the manner shown in Fig. 10,along the line of the wire F, and they are then bent` over, as shown inFig. ll. The two semicircular sections or lips are then clasped upon themetal-coated end of the filament to which it is applied, and, if it isso desired, they may be soldered thereto in any convenient manner.

The two conducting-wires are secured to each other by means of a bridge,f2, of glass. This bridge consists merely of a small section of glasstube having the conducting-wires inserted through it and let into itsrespective sides by softening the glass or by molding the glass aboutthe wires. The bridge-piece may be applied either before or after thelament has been clamped to the wires.

The filament and the conducti1ig-wires having been prepared in thismanner, they are placed within the globe. The diameter, however, of thecurve of the filament is preferably made somewhat greater than thediameter of the opening into the globe. for the purpose of giving to thelamp a capacity for giving light as great as possible and for renderingthe size of the globe as small as possible relatively to the length ofthe filament. It is therefore necessary to first insert the loop h3 ofthe filament into the globe and to spring the entire lament in byslightly bending the double loop during the process. When, however, theloop is once within the globe, it resumes its normal shape and form.

Referring. now to the form and method of constructing the vacuum-chamberand of closing the same, A represents a cylindrical glass tube, at theend of which is a bulb, B, which is preferably formed by blowing into asuitable mold. The bulb B is made of the size which it is desired thatthe lamp shall have. Instead of blowing'it in a mold, however, it may beblown directly on thepunty from the metal in the glass-makers Crucible,or from a tube of any diameter. The globe, it will be particularlynoticed, is thus formed without any projection at the side opposite thetube A, but with an entirely smooth surface. The tube or neck is thennarrowed toward the contraction,where it is to be finally closed. Theglobe is placed in a lathe, and a portion of the neck or tube A is cutoff at a point on the curved part which is of less diameter than theneck, as indicated, along the line x x in Fig. 12, leaving a short neck,about one-half IOO l sitions which the two pieces of an inch in' length.Before the section of the neck is cut off, however, a mark is preferablyput upon the same to indicate the pooriginally occupied, so that theportion a of the neck or tube can be reapplied to the portion a afterthe filament and conductors have been inserted in the globe B. Thecarbon filament, the form and manufacture of which has already beendescribed, is then inserted within the bulb or globe B, the portion h3being first inserted through the neck a, and the filament being thenbent in such a manner as to allow its entire length to be pushedforwardV into the interior of the globe. The flexibility of the filamentwill permit this to be accomplished, although it would not be possibleto bend the two sides of the curved filament toward each othersufficiently to permit the filament to be inserted in a iiattened form.This method of insertion is also applicable to other forms of filaments.After the lament is within the globe it will immediately resume itsprevious form. After the filament H is placed within the globe theconducting-wires F F, which sustain the-same, are caused to rest acrossthe edge b of the neck a of the globe B in the manner indicated in Fig.9, and the latter is, by means of a blow-pipe or in any other suitablemanner, heated sufficiently to soften the glass around theconducting-wires and to allow themto sink by their own weight into theedge' of the neck, forming slight depressions. The glass,however, willclose over the conductors, thus completely embedding them in the neck ofthe globe and securing a tight joint, or a small piece of glass may beadded to each conductor for that purpose, if necessary.

The next step in the process consists in replacing the section a of thetube A upon the neck a of the globe. The marks which were applied beforethe section was eut off or removed serve to guide the workman inreplacing the latter in the precise position which it at first occupied.By means of a blow-pipe or in any other suitable manner the two portionsof the glass are then welded together along the line x1 x', as shown inFig. 10, and the lamp resumes its former shape, the filament H and theconductors F having been inserted. It will be understood, moreover, thatthe two portions vof the globe are entirely homogeneous and that thedisadvantage of having glass of different thicknesses or differentqualities in the lamp is entirely avoided. A platinum stopper, d, havingat one end a loop or head, e, is then insertedwithin the narrowedopening of the globe or neck, and the tube is narrowed sufflciently toprevent this stopper from falling out. IThe lamp is then applied to anairpump, by means of which the air is exhausted from the chamber. Whenthe vacuum has been formed in the chamber B, the neck of the globe isclosed about the platinum stopper d, thus forming a tight joint. It isnot found y below the point necessary in so closing the globe to form atemporary sealing at some distance below the point where the globe ispermanently closed, as is usually customary inA other forms' of lamp,but the lamp may be closed once for all while still upon the air-pump;and it may be further observed that since the point of closing is at theend of the globe which enters the holder it may be made at such adistance from the globe as may be desired, whereas, in a lamp which issealed at the other extremity of the globe, it is necessary to form thefinal"\..`

ing to be done at the glass-blowers table`instead of on the been closedthe pump. After the lamp Vhas neck formed or extending of closure may bereadily broken off or removed. The unnecessary portion of the platinumstopper may, H by means of any suitable tools, and ground down even withthe glass tube, or the neck may be drawn downto a break, and then onlythe stopper is required to be cut off. p

Itiswell known that platinum when cooled sends out gases which areoccluded in the 'metal while it is heated, and for the purpose ofpreventing such gases from escaping from the stopper into the glass orthe tubeit is advisable to conduct the process of closing the glassaround the stopper at as low a temperature as possible, or it maysometimes be preferred to coat the latter 'with a thin lm of glasspreparatory to inserting it within the globe. By reason of this film ofglass gases would not be given off which were occluded before theclosing of the globe. The glass, as it is closed about the stopper,enters the pores at the surface of the platinum stopper and formsatghtjoint without forming anychemical union therewith. Such a iilm ofglass is preferably applied by first inserting the platinum wire into atightly-fitting glass tube, then placing the same in a suitable chamberand exhausting the air therefrom. Vhile thus in a vacuum the platinumwire is heated to iucandescence. The gases are thus driven then be cutof IOO IIO

out from the platinum, and the glass then enters the pores of theplatinum by reason of the capillary attraction, and in this manner avery close mechanical contact is formed between the two materials. Thevacuumchamber may, if it is so desired, be allowed to suddenly fill withair while the platinum is still heated, and the glass will then bebrought under a pressure which insures that it will penetrate the poresof i the platinum. Not only may the platinum stopper be thus treated,but the conductors leading to the filament may also be treated in thesame manner.V

The platinum-stopper may, instead of being cut off at the end of thebeak, be allowed to protrude, and then it may be bent into a loop, asshown in Fig. 10, for the purpose of affording a convenient means ofhanging the lamp.

It is desired also to call attention to the fact that the stopper may beplaced at the end of the lamp opposite the neck, the usual projectionbeing formed at that end for the purpose.

It remains now to describe the holder which it is preferable to employfor sustaining the lamp in position. Such holder is illustrated in Figs.1l and l2. Referring to these igures, It represents a suitable calyx ofthe proper size for receiving the neck B of the lamp.. In this calyx theneck is designed to fit and to be held securely by means of suitablelugs, r', which are Ydesigned to enter depressions r2 formed in thesides of the neck of the lamp. These depressions are formed While theshank about the lamp is still softened by heat.

Soldered to the ends of the supporting couductors F are suitableconductin g-wi res, s and s2, which extend to the lower end of thesupporting-calyx It, and through these condul tors it is designed thatthe connections of the lamp shall be completed. For this purpose a plugor nut, S', is inserted at the lower extremity of the ealyx R, andeither screwed into the same Yor tightly fastened in any suitablemanner. In the lower ends of the nut or plug there is set a ring, t, ofconducting material, surrounding a disk, t2, of like material. The diskand ring are insulated from each other, the nut itself being ofinsulating material. The conductor s is soldered to the ring t', whilethe conductor s2 is united with the disk t2. The ring and the disk bothpreferably project a slight distance beyond the face of the nut.

Asecond'nut, S', is designedto be applied to the extremity of the calyxR, and this nut is providedwith a ring, t3, and disk t, similar to theparts t and The second nut, S2, by being screwed into the case or calyxR, brings the two rings against each other, and likewise the two disks,thus making two perfect electrical connections The ring t3 and the diskt are respectively provided with conductors s3 and s4, which areconnected with the connectingwires of the system in which the lamp is tobe employed, so that either by screwing the calyx upon the neck or thelatter into the calyx thelamp will be placed in circuit.

Ylt is understood that suitable circuit-interrupting devices may beapplied to the supporting-calyx, as desired. Instead of two of thedepressions and lugs formed in the neck of the lamp for securing thecalyx, any number may be employed, and they may be extended throughoutthe length of the neck, if so desired, for the purpose of preventing thelamp from being turned when in position; or the side of the neck may beflattened, if it is found desirable.

I claim as my inventionl. A filament for incandescent electriclamps,formed in the shape of two incomplete circles united with each other bya curved continuation, substantially as described.

2. A filament forincandescent electriclamps, formed in the shape of twoincomplete circles having different radii and united with each other bya curved continuation, substantially as described.

3. A filament for incandescent electric lights, consisting of aconductor formed in an arched loop the sides of which are united by acurved continuation, are approximately parallel, and are bent to formcurves, the free ends of which loop are supported, substantially asdescribed.

4. Aiilament for incandescent electriclamps, consisting of a loop ofincandescent material, the sides of which are bent so as to form twoincomplete circles, and are united with each other by a curvedcontinuation, substantially as described.

5f A carbon lament for incandescent electric lamps, having itsrespective extremities electroplated with metal before being attached tothe conductors, and having its ends bare, substantially as described, incombination with supporting-conductors, to which it is secured bymechanical compression.

6. A carboniilament for incandescent electrie lamps, having its outerextremities covered with a metal which has been applied byelectro-deposition, and its ends bare, substantiully as described.

7. A carbon filament for incandescent lamps, having its extremitiesfirst coated with a metal by electro deposition, in combination withsupporting-conductors, to which it is united by mechanical compressionand with which it is afterward soldered, substantially as de scribed.

8. A carbon lament for incandescent electric lamps, having its endsfirst coated by electro-deposition, in combination with metallicsupporting-conductors,to which the respective ends so coated are securedby mechanical compression, substantially as described.

9. An incandescent electric lamp having a carbon lament formed in acurve of greater diameter than the diameter of the opening through.which it was inserted. 10. In combination with the inclosingcham ber ofan incandescent electric light, a carbonized filament formed intoaloophavinga curved bight,which loop is constructed in a curve the radius ofwhich is greater than that of the opening through which it isninsertedinto the chamber.

In testimony whereof I have hereunto subscribed my name this 26th day ofJuly, A. D. 1884:.

OTTO A. MOSES.

W'itnesses:

CARRIE E. DAvIDsoN, GHARLRs A. TERRY.

IIO

